Intrafractional motion reduction system using audiovisual-aided interactive guidance and related methods thereof

ABSTRACT

A system and method for reducing intrafractional motion of a subject The system includes a subject user device, whereby the user device includes an image acquisition device configured to receive location marker information of the subject to provide location marking data of the subject. The system may also include a digital processor configured to: receive the location marking data and determine movement of the subject relative to the location marker information; and communicate feedback of the movement to the subject to help the subject reduce intrafractional motion.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims benefit of priority under 35 U.S.C.§119(e) from U.S. Provisional Application Ser. No. 62/057,361, filedSep. 30, 2014, entitled “Personal Digital Assistant (PDA) with RetinaDisplay for Intrafractional Motion Reduction as a Remote-Controlled andSelf-Contained Audiovisual Biofeedback System” and U.S. ProvisionalApplication Ser. No. 62/233,554, filed Sep. 28, 2015, entitled “PersonalDigital Assistant (PDA) with Retina Display for Intrafractional MotionReduction as a Remote-Controlled and Self-Contained AudiovisualBiofeedback System”; the disclosure of which are hereby incorporated byreference herein in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to the field of managingintrafractional motion. More specifically, the invention relates to thesubfield and using a self-contained audiovisual-aided interactivesystem.

BACKGROUND

Patient motion is one of prevalent concerns in medical imaging andradiation treatment delivery.¹ (See L. Xing, Z.-X. Lin, S. S. Donaldson,Q. T. Le, D. Tate, D. R. Goffinet, S. Wolden, L. Ma, A. L. Boyer,“Dosimetric effects of patient displacement and collimator and gantryangle misalignment on intensity modulated radiation therapy,”Radiotherapy and Oncology 56, 97-108 (2000), of which is incorporated byreference herein.) If not properly managed during radiotherapy, it canresult in insufficient dose delivery to the target and/or unnecessaryirradiation of surrounding healthy tissues. A number of diverse motionmanagement techniques have been proposed for various disease sites suchas simple face mask, bite block, and more aggressive head-frame forbrain/H&N (head and neck) immobilization,²⁻⁴ and motion-encompassing,active breath control, and real-time tumor tracking for breathing motionmanagement.^(5, 6) Moreover, most of the motion management systems areintolerable for claustrophobic patients. For example, only a fewimmobilization systems such as open-face mask and head mold with a biteplate are available for the claustrophobic patients, but they are mainlymask-based and make the patients passive recipient of care with acertain degree of discomfort. (See G. Li, D. M. Lovelock, J. Mechalakos,S. Rao, C. Della-Biancia, H. Amols, N. Lee, “Migration from full-headmask to “open-face” mask for immobilization of patients with head andneck cancer,” Journal of Applied Clinical Medical Physics 142013, ofwhich is incorporated by reference herein).

While most motion management techniques are mainly operator driven,there are evidences that patient interactive (or biofeedback) mechanismcan enhance their performance. The concept of patient interactiveimmobilization for brain/H&N was first introduced by Kim and Helmig,⁷and Kim et al. demonstrated feasibility of the concept using a simplelaser-based device.⁸ Similar approaches, under the name of audiovisual(AV) biofeedback, have been widely studied for the management of tumormovement caused by respiratory motion.^(6, 9, 10) For instance, severalresearch groups demonstrated that AV biofeedback could significantlyreduce respiratory irregularities during medical imaging or radiationtreatment.^(6, 9, 10) Lim et al. also showed significant improvements inbreathing motion regularities through a visual guidance system.¹¹Additionally, Arnold et al. decreased respiratory motion artifacts inMRI through active breath control (ABC).¹² An interesting concept ofquasi-breath-hold (QBH) was also possible by virtue of AVbiofeedback.^(13, 14)

Though these studies have demonstrated improvements in intrafractionalmotion management, most systems employ tools that are relativelycomplicated and costly, which causes certain extent of limitation intheir accessibility by patients and flexibility in clinical use. Forexample, AV biofeedback often utilizes the real-time positioningmanagement (RPM) system (Varian Medical Systems, Palo Alto, USA) formotion tracing, and the breath-regulation system by Lim et al. requiresa respiration-monitoring mask together with a thermocouple. The ABCsystem utilized by Arnold et al. also necessitates a spirometer and apneumotachograph.

The disclosed system is directed toward improving the efficiency andrelated complications of managing intrafractional motion.

Overview

In radiotherapy, one of prevalent concerns for accurate treatmentdelivery is voluntary movement by the patient. An aspect of anembodiment of the present invention provides, but not limited thereto, aremote-controlled and self-contained audiovisual (AV)-aided interactivesystem with the personal digital assistant (PDA) (such as an iPad minior the like; as well as other processor based systems or other machineas desired or required) with Retina display, easily obtainable andcost-effective tablet computers, for intrafractional motion reduction inbrain/H&N (head and neck) radiotherapy.

An aspect of an embodiment of the present invention provides, but notlimited thereto, a system for reducing intrafractional motion of asubject. The system may comprise a subject user device, whereby the userdevice may comprise an image acquisition device configured to receivelocation marker information of the subject to provide location markingdata of the subject. The system may comprise: a digital processorconfigured to: receive the location marking data and determine movementof the subject relative to the location marker information; andcommunicate feedback of the movement to the subject to help the subjectreduce intrafractional motion.

An aspect of an embodiment of the present invention provides, but notlimited thereto, a computer implemented method for reducingintrafractional motion of a subject. The method may comprise: receivinglocation marker information of the subject and generating locationmarking data of the subject; digitally processing the location markingdata and determining movement of the subject relative to the locationmarker information; and communicating feedback of the movement to thesubject to help the subject reduce intrafractional motion.

An aspect of an embodiment of the present invention provides, but notlimited thereto, a non-transitory machine readable medium includinginstructions for reducing intrafractional motion of a subject, whichwhen executed by a machine, cause the machine to: receive locationmarker information of the subject and generate location marking data ofthe subject; determine movement of the subject relative to the locationmarker information; and transmit to an output module to communicatefeedback of the movement to the subject to help the subject reduceintrafractional motion.

These and other objects, along with advantages and features of variousaspects of embodiments of the invention disclosed herein, will be mademore apparent from the description, drawings and claims that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a partof the instant specification, illustrate several aspects and embodimentsof the present invention and, together with the description herein,serve to explain the principles of the invention. The drawings areprovided only for the purpose of illustrating select embodiments of theinvention and are not to be construed as limiting the invention.

FIG. 1(A) is a screenshot of a self-contained AV-aided interactivesystem of iPad minis with Retina display that is shown with the sessionsetup. The AV-aided interactive tablet (or AV-guidance tablet) and theremote control tablet are shown at the treatment room.

FIG. 1(B) is a screenshot of a green disk over top of a blue disk (notshown) that was shown at the center of the display as a reference forthe guiding disk.

FIG. 1(C) is a screenshot of the color of the circle graduallytransitioned from green to red as the motion delta increases from zeroto a predetermined warning distance (for example, 2 mm for this study).

FIG. 2(A) is a screenshot of a set up of the temporal accuracy andresolution that was studied with the QUASAR motion phantom, whichincluded the AV-aided interactive tablet (or AV-guidance tablet) andremote control tablet.

FIGS. 2(B) and 2(C) are screenshots that graphically illustrate thehorizontal (x-direction) and vertical (y-direction) components,respectively, of the real-time motion as measured by the AV-aidedinteractive tablet; and showed the mean displacement with horizontal andvertical data separate after the session.

FIGS. 3 (A) and 3(B) are screenshots pertaining to the first study withone marker whereby the intrafractional voluntary head motions of fivevolunteers with one marker are graphically shown without AV-aidedinteractive guidance and with AV-aided interactive guidance,respectively. The mean displacement decreased vertically by an averageof 88% and horizontally by an average of 77% with AV guidance.

FIGS. 4(A) and 4(B) are screenshots pertaining to the second study withtwo markers whereby the intrafractional voluntary head motions of fivevolunteers with two markers are shown without AV-aided interactiveguidance and with AV-aided interactive guidance, respectively. The meandisplacement decreased vertically by an average of 90% and horizontallyby an average of 83% with AVguidance.

FIG. 5 is a block diagram illustrating an example of a machine uponwhich one or more aspects of embodiments of the present invention can beimplemented.

FIG. 6 provides a screenshot of a geometric representation of thepatient's head rotation with respect to the camera, assuming that theback of the head is anchored by the head rest, where h is the length ofthe head from the forehead to the back of the head, δ is the symbol oflinear displacement, c is the distance from the camera to the marker atδ=0, Δ is the actual linear displacement of the marker caused by thehead rotation of θ, Φ is the angle of the camera seeing the displacedmarker, d is the distance from the camera to the marker at δ=Δ, and Ω isthe calculated displacement by the system.

FIGS. 7(A) and (B) provide screenshots of the intrafractional voluntaryhead motions of the volunteer 8 (representative of the 90th percentilerange of reduced the mean displacement due to AV-aided interactiveguidance) as shown without AV-aided interactive guidance (“No guidance”)and with AV-aided interactive guidance, respectively. The meandisplacement decreased superior-inferiorly (SI-direction) by an averageof 94% (from 3.5 mm to 0.2 mm) and right-left direction (RL-direction)by an average of 85% (from 0.7 mm to 0.1 mm) with AV-aided interactiveguidance.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION

In an approach, the self-contained AV-aided interactive system (andrelated method and computer readable medium) utilized two tabletcomputers: one for audiovisual guidance for the subject and the otherfor remote control by an operator. The tablet for audiovisual guidancetraced the motion of a colored marker using the built-in front-facingcamera, and the remote control tablet at the control room usedinfrastructure Wi-Fi networks for real-time communication with the othertablet (tablet for the audiovisual guidance). The marker was tracedusing a color-based motion-tracking algorithm. In an evaluation, aprogrammed QUASAR motion phantom was used to test the temporal andpositional accuracy and resolution. In addition, position data were alsoobtained from eight healthy volunteers in two studies (one study withone marker and other with two markers) with and without guidance toevaluate the reduction of intrafractional head motion.

An aspect of an embodiment of the present invention provides, but notlimited thereto, a personal digital assistant (PDA) with retina displayfor intrafractional motion reduction as a remote-controlled andself-contained audiovisual-aided interactive system.

As disclosed herein, a purpose of a study by the present inventors,among other things, was to develop and evaluate a novelremote-controlled and self-contained AV-aided interactive tool usingeasily obtainable and cost-effective tablet computers (or otherprocessor based systems or other machines as desired or required). Forinstance, two iPad minis with Retina display (Model A1489; Apple Inc.,Cupertino, USA) were chosen and mobile applications were developed toprovide a more accessible and flexible platform for AV-aided interactiveguidance for minimizing intrafractional motion. For feasibility testpurpose, the performance of the system was investigated in terms ofresolution, accuracy, and its effectiveness on intrafractional headmotion management of human subjects simulating a claustrophobic brain orH&N case were evaluated.

An aspect of an embodiment of the present invention included a studyproviding a real-time remote-controlled audiovisual-aided interactiveguidance that was achieved using a self-contained system of tabletcomputers. In the phantom study, the temporal and positional resolutionwas 24 Hz and 0.2 mm. In the volunteer study, the average vertical andhorizontal displacement was reduced from 3.2 mm to 0.4 mm and from 1.3mm to 0.3 mm with audiovisual guidance, respectively. The vertical andhorizontal baseline shift was reduced from 0.8 mm/min to 0.06 mm/min andfrom 0.3 mm/min to 0.06 mm/min with audiovisual guidance. This studydemonstrated, among other things, a reduction in intrafractional headmotion using a remote-controlled and self-contained audiovisual(AV)-aided interactive system of PDAs (such as iPad minis, or othertypes of tablets or the like) with Retina display, easily obtainable andcost-effective tablet computers. This system and related method canstreamline clinical flow with the proposed remote-controlled andself-contained system and by allowing patients to practice self-motionmanagement before radiation treatment delivery.

An aspect of an embodiment of the present invention included a studywhereby in the evaluation, a programmed QUASAR motion phantom was usedto test the temporal and position accuracy and resolution. Position datawere also obtained from ten healthy volunteers with and without guidanceto evaluate the reduction of intrafractional head motion in simulationsof a claustrophobic brain or H&N case. In the phantom study, thetemporal and positional resolution was 24 Hz and 0.2 mm. In thevolunteer study, the average superior-inferior and right-leftdisplacement was reduced from 3.2 mm to 0.4 mm and from 1.3 mm to 0.2 mmwith AV-aided interactive guidance, respectively. The superior-inferiorand right-left positional drift was reduced from 0.8 mm/min to 0.1mm/min and from 0.3 mm/min to 0.1 mm/min with audiovisual-aidedinteractive guidance. This study demonstrated a reduction inintrafractional head motion using a remote-controlled and self-containedAV-aided interactive system of iPad minis with Retina display, easilyobtainable and cost-effective tablet computers. This approach canstreamline clinical flow for claustrophobic patients without a head maskand by allowing patients to practice self-motion management beforeradiation treatment delivery.

In an aspect of an embodiment of the present invention, of which may bereferenced by FIG. 1(A), as a general but non-limiting approach,provided is a system for reducing intrafractional motion of a subject 9.The system may comprise a subject user device 21 that includes an imageacquisition device configured to receive location marker information ofthe subject 9 to provide location marking data of the subject 9. Thedigital processor may be configured to receive the location marking dataand determine movement of the subject 9 relative to the location markerinformation. The digital processor may be further configured tocommunicate feedback of the movement to the subject 9 to help thesubject 9 reduce intrafractional motion. The communication feedback tothe subject 9 may be accomplished in real time. The communicationfeedback of the movement to the subject 9 may be include a visualdisplay, audio signal, or both visual and audio. The visual display maybe a display panel disposed in or in communication with the subject userdevice 21 and which is viewable by the subject 9. The digital processordetermines a reference point and a movement point, whereby the referencepoint represents a starting position of the subject 9; and the movementpoint represents an indication of intrafractional motion of the subject9. The display panel may include a display reference point and a displaymovement point, whereby reference point represents to a subject astarting position of the subject 9; and the display movement pointrepresents to a subject an indication of intrafractional motion of thesubject 9. The display reference point may be a first color having apreselected pattern, and the display movement point may be a secondcolor having a preselected pattern, whereby the intrafractional motioncauses the display movement point to move relative to the referencepoint, and that which is discernable to the subject 9. The audio signalmay be provided by a speaker in communication with the subject userdevice 21 and which is audible to the subject 9. The system may furtherinclude an operator device 41. The operator device 41 may include anoperator digital processor configured to communicate with the subjectuser device 21. The operator digital processor is configured to controland/or monitor the subject user device 21. The operator device 41 mayinclude at least one of the following: video display, alpha-numericinput device, or UI navigation device for controlling or monitoring thesubject user device 21. Similarly, subject user digital processor may beconfigured to control the subject user device 21. The location markerinformation of the subject 9 is provided by the following: a markingsubstrate that is disposed on the subject; a location that is identifiedon the subject; or a combination of disposing a marking substrate on thesubject and identifying a location on the subject. Alternatively, thedetermination of movement of the subject may be provided by theprocessor configuring a geometric representation of rotation of the headof the subject. For example, the geometric representation of rotation ofthe head of the subject (or may be other region(s) of the subject asdesired, required, or needed) is provided according to the followingcharacteristics: h, wherein h is the length of the head from theforehead to the back of the head, δ, wherein δ is the symbol of lineardisplacement, c, wherein c is the distance from the image acquisitiondevice (e.g., camera) to a marker at δ=0, Δ, wherein Δ is the actuallinear displacement of the marker caused by the head rotation of θ, Φ,wherein Φ is the angle of the image acquisition device seeing thedisplaced marker, d, wherein d is the distance from the acquisitiondevice to the marker at δ=Δ, and Ω, wherein Ω is the calculateddisplacement by the system.

FIG. 5 is a block diagram illustrating an example of a machine uponwhich one or more aspects of embodiments of the present invention can beimplemented.

FIG. 5 illustrates a block diagram of an example machine 400 upon whichone or more embodiments (e.g., discussed methodologies) can beimplemented (e.g., run).

Examples of machine 400 can include logic, one or more components,circuits (e.g., modules), or mechanisms. Circuits are tangible entitiesconfigured to perform certain operations. In an example, circuits can bearranged (e.g., internally or with respect to external entities such asother circuits) in a specified manner. In an example, one or morecomputer systems (e.g., a standalone, client or server computer system)or one or more hardware processors (processors) can be configured bysoftware (e.g., instructions, an application portion, or an application)as a circuit that operates to perform certain operations as describedherein. In an example, the software can reside (1) on a non-transitorymachine readable medium or (2) in a transmission signal. In an example,the software, when executed by the underlying hardware of the circuit,causes the circuit to perform the certain operations.

In an example, a circuit can be implemented mechanically orelectronically. For example, a circuit can comprise dedicated circuitryor logic that is specifically configured to perform one or moretechniques such as discussed above, such as including a special-purposeprocessor, a field programmable gate array (FPGA) or anapplication-specific integrated circuit (ASIC). In an example, a circuitcan comprise programmable logic (e.g., circuitry, as encompassed withina general-purpose processor or other programmable processor) that can betemporarily configured (e.g., by software) to perform the certainoperations. It will be appreciated that the decision to implement acircuit mechanically (e.g., in dedicated and permanently configuredcircuitry), or in temporarily configured circuitry (e.g., configured bysoftware) can be driven by cost and time considerations.

Accordingly, the term “circuit” is understood to encompass a tangibleentity, be that an entity that is physically constructed, permanentlyconfigured (e.g., hardwired), or temporarily (e.g., transitorily)configured (e.g., programmed) to operate in a specified manner or toperform specified operations. In an example, given a plurality oftemporarily configured circuits, each of the circuits need not beconfigured or instantiated at any one instance in time. For example,where the circuits comprise a general-purpose processor configured viasoftware, the general-purpose processor can be configured as respectivedifferent circuits at different times. Software can accordinglyconfigure a processor, for example, to constitute a particular circuitat one instance of time and to constitute a different circuit at adifferent instance of time.

In an example, circuits can provide information to, and receiveinformation from, other circuits. In this example, the circuits can beregarded as being communicatively coupled to one or more other circuits.Where multiple of such circuits exist contemporaneously, communicationscan be achieved through signal transmission (e.g., over appropriatecircuits and buses) that connect the circuits. In embodiments in whichmultiple circuits are configured or instantiated at different times,communications between such circuits can be achieved, for example,through the storage and retrieval of information in memory structures towhich the multiple circuits have access. For example, one circuit canperform an operation and store the output of that operation in a memorydevice to which it is communicatively coupled. A further circuit canthen, at a later time, access the memory device to retrieve and processthe stored output. In an example, circuits can be configured to initiateor receive communications with input or output devices and can operateon a resource (e.g., a collection of information).

The various operations of method examples described herein can beperformed, at least partially, by one or more processors that aretemporarily configured (e.g., by software) or permanently configured toperform the relevant operations. Whether temporarily or permanentlyconfigured, such processors can constitute processor-implementedcircuits that operate to perform one or more operations or functions. Inan example, the circuits referred to herein can compriseprocessor-implemented circuits.

Similarly, the methods described herein can be at least partiallyprocessor-implemented. For example, at least some of the operations of amethod can be performed by one or processors or processor-implementedcircuits. The performance of certain of the operations can bedistributed among the one or more processors, not only residing within asingle machine, but deployed across a number of machines. In an example,the processor or processors can be located in a single location (e.g.,within a home environment, an office environment or as a server farm),while in other examples the processors can be distributed across anumber of locations.

The one or more processors can also operate to support performance ofthe relevant operations in a “cloud computing” environment or as a“software as a service” (SaaS). For example, at least some of theoperations can be performed by a group of computers (as examples ofmachines including processors), with these operations being accessiblevia a network (e.g., the Internet) and via one or more appropriateinterfaces (e.g., Application Program Interfaces (APIs).)

Example embodiments (e.g., apparatus, systems, or methods) can beimplemented in digital electronic circuitry, in computer hardware, infirmware, in software, or in any combination thereof. Exampleembodiments can be implemented using a computer program product (e.g., acomputer program, tangibly embodied in an information carrier or in amachine readable medium, for execution by, or to control the operationof, data processing apparatus such as a programmable processor, acomputer, or multiple computers).

A computer program can be written in any form of programming language,including compiled or interpreted languages, and it can be deployed inany form, including as a stand-alone program or as a software module,subroutine, or other unit suitable for use in a computing environment. Acomputer program can be deployed to be executed on one computer or onmultiple computers at one site or distributed across multiple sites andinterconnected by a communication network.

In an example, operations can be performed by one or more programmableprocessors executing a computer program to perform functions byoperating on input data and generating output. Examples of methodoperations can also be performed by, and example apparatus can beimplemented as, special purpose logic circuitry (e.g., a fieldprogrammable gate array (FPGA) or an application-specific integratedcircuit (ASIC)).

The computing system can include clients and servers. A client andserver are generally remote from each other and generally interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other. Inembodiments deploying a programmable computing system, it will beappreciated that both hardware and software architectures requireconsideration. Specifically, it will be appreciated that the choice ofwhether to implement certain functionality in permanently configuredhardware (e.g., an ASIC), in temporarily configured hardware (e.g., acombination of software and a programmable processor), or a combinationof permanently and temporarily configured hardware can be a designchoice. Below are set out hardware (e.g., machine 400) and softwarearchitectures that can be deployed in example embodiments.

In an example, the machine 400 can operate as a standalone device or themachine 400 can be connected (e.g., networked) to other machines.

In a networked deployment, the machine 400 can operate in the capacityof either a server or a client machine in server-client networkenvironments. In an example, machine 400 can act as a peer machine inpeer-to-peer (or other distributed) network environments. The machine400 can be a personal computer (PC), a tablet PC, a set-top box (STB), aPersonal Digital Assistant (PDA), a mobile telephone, a web appliance, anetwork router, switch or bridge, or any machine capable of executinginstructions (sequential or otherwise) specifying actions to be taken(e.g., performed) by the machine 400. Further, while only a singlemachine 400 is illustrated, the term “machine” shall also be taken toinclude any collection of machines that individually or jointly executea set (or multiple sets) of instructions to perform any one or more ofthe methodologies discussed herein.

Example machine (e.g., computer system) 400 can include a processor 402(e.g., a central processing unit (CPU), a graphics processing unit (GPU)or both), a main memory 404 and a static memory 406, some or all ofwhich can communicate with each other via a bus 408. The machine 400 canfurther include a display unit 410 (or audio unit), an alphanumericinput device 412 (e.g., a keyboard), and a user interface (UI)navigation device 414 (e.g., a mouse). In an example, the display unit410, input device 412 and UI navigation device 414 can be a touch screendisplay. The machine 400 can additionally include a storage device(e.g., drive unit) 416, a signal generation device 418 (e.g., aspeaker), a network interface device 420, and one or more sensors 421,such as a global positioning system (GPS) sensor, compass,accelerometer, image acquisition or recording device, or other sensor.

The storage device 416 can include a machine readable medium 422 onwhich is stored one or more sets of data structures or instructions 424(e.g., software) embodying or utilized by any one or more of themethodologies or functions described herein. The instructions 424 canalso reside, completely or at least partially, within the main memory404, within static memory 406, or within the processor 402 duringexecution thereof by the machine 400. In an example, one or anycombination of the processor 402, the main memory 404, the static memory406, or the storage device 416 can constitute machine readable media.

While the machine readable medium 422 is illustrated as a single medium,the term “machine readable medium” can include a single medium ormultiple media (e.g., a centralized or distributed database, and/orassociated caches and servers) that configured to store the one or moreinstructions 424. The term “machine readable medium” can also be takento include any tangible medium that is capable of storing, encoding, orcarrying instructions for execution by the machine and that cause themachine to perform any one or more of the methodologies of the presentdisclosure or that is capable of storing, encoding or carrying datastructures utilized by or associated with such instructions. The term“machine readable medium” can accordingly be taken to include, but notbe limited to, solid-state memories, and optical and magnetic media.Specific examples of machine readable media can include non-volatilememory, including, by way of example, semiconductor memory devices(e.g., Electrically Programmable Read-Only Memory (EPROM), ElectricallyErasable Programmable Read-Only Memory (EEPROM)) and flash memorydevices; magnetic disks such as internal hard disks and removable disks;magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 424 can further be transmitted or received over acommunications network 426 using a transmission medium via the networkinterface device 420 utilizing any one of a number of transfer protocols(e.g., frame relay, IP, TCP, UDP, HTTP, etc.). Example communicationnetworks can include a local area network (LAN), a wide area network(WAN), a packet data network (e.g., the Internet), mobile telephonenetworks (e.g., cellular networks), Plain Old Telephone (POTS) networks,and wireless data networks (e.g., IEEE 802.11 standards family known asWi-Fi®, IEEE 802.16 standards family known as WiMax®), peer-to-peer(P2P) networks, among others. The term “transmission medium” shall betaken to include any intangible medium that is capable of storing,encoding or carrying instructions for execution by the machine, andincludes digital or analog communications signals or other intangiblemedium to facilitate communication of such software.

EXAMPLES

Practice of the invention will be still more fully understood from thefollowing examples and experimental results, which are presented hereinfor illustration only and should not be construed as limiting theinvention in any way.

Example and Experimental Results Set No. 1 Methods and Materials A.Self-Contained AV-Aided Interactive System

An aspect of an embodiment of the present invention system that wasdeveloped includes, but not limited thereto, two tablet computers (iPadminis with Retina display, Model A1489). One unit (i.e., iPad mini #1)provides AV-aided interactive guidance to the subject inside thetreatment/simulation room, and the other unit (i.e., iPad mini #2) isused for remotely controlling the AV-aided interactive device (i.e.,iPad mini #1).

For interactive guidance, 1) a marker (colored and non-reflective) isattached on the skin of the patient, 2) the unit #1 continuouslycaptures the image of the marker (in 1280-by-720 resolution using thebuilt-in front-facing FaceTime HD camera), 3) image analysis is carriedout by the application developed to determine the position of the marker(consequently that of the patient), and 4) both the current andreference marker positions are displayed so that the patient canfeedback in real-time.

The marker position is determined by filtering the background based onthe marker's color;¹⁵ and a green or blue marker is preferred tomaximize signal-to-noise ratio. Both image processing and analysis aredone with OpenCV for iOS (version 2.4.9, supported by Willow Garage andItseez). The calculations are done in pixels first then converted tomillimeters. For the pixel-to-mm conversion, a mm-to-pixel ratio isobtained with the marker's maximum length in pixels measured by thecamera and a predetermined length in mm. For example, themillimeter-to-pixel ratio was 0.1 mm/pixel at 14 cm and 0.2 mm/pixel at25 cm. The motion data is then relayed to the subject through AV-aidedinteractive guidance in real-time on the same tablet unit.

For visual feedback, the tablet displays the horizontal (x-direction)and vertical (y-direction) components of the real-time motion delta bytranslating a translucent disk on the iPad's display (2048-by-1536resolution) as shown in FIG. 1. A blue disk (not shown as it's coveredby a green disk 3) is shown at the center of the display as a referencefor the guiding disk. To ease the cognitive load of the perception ofthe motion delta's magnitude, the color of the circle gradually changesfrom green 3 (as shown in FIG. 1(B)) to red 7 as the motion deltaincreases from ‘zero’ to a predetermined warning distance (2 mm for thisstudy) as illustrated in FIG. 1(C). Partial view of the blue disk 5 canbe observed in FIG. 1(C). It should be appreciated that various colors,designs, shapes and patterns may be implemented as desired, required, orneeded—as well as their associated sequence timing.

The audio component of AV-aided interactive system produces short beepsthat gradually increase in frequency as the motion delta from thereference point becomes larger. When motion delta is smaller than 10% ofthe designated warning distance, no beeps are generated. When the motiondelta reaches to and becomes greater than the designated warningdistance, the frequency of beeps gets plateaued. It should beappreciated that various audio tones, pitches, and volumes may beimplemented as desired, required, or needed—as well as their associatedsequence timing.

B. Evaluation of Basic Characteristics

The positional accuracy and resolution of the system were investigatedthrough a phantom study using a programmable QUASAR motion phantom(Modus Medical Devices Inc., London, Canada) 61 shown in FIG. 2(A). Thereference marker was moved with three different positions (10 mm, 20 mmand 30 mm) using the programmed QUASAR motion phantom 61 while themotion was detected and recorded by the tracking device. Tests were madein three different levels of marker used, such as one marker, twomarkers with parallel or perpendicular motion and three markers with thetriangular configuration: 15 cm of the marker plane-to-camera distance.The temporal accuracy and resolution of the system were studied with theQUASAR motion phantom 61 which was set to oscillate with a peak-to-peakamplitude of 10 mm in a five second period. The temporal accuracy wasdetermined by averaging all peak-to-peak periods measured by the system.Referring to FIGS. 2(B) and 2(C), the AV-aided interactive tabletmeasured the horizontal (x-direction) and vertical (y-direction)components, respectively, of the real-time motion and showed the meandisplacement with horizontal and vertical data separate after thesession.

C. Feasibility Test with Human Subjects

A feasibility study for intrafractional head motion management wasperformed to investigate the effectiveness of the system. To beconservative, simulation was carried out under the assumption thatpatients were claustrophobic, meaning completely no immobilizationdevice other than a headrest provided.

Eight healthy volunteers (age: 30.2±11.2, age range: 20˜52) participatedin the study and their voluntary head motion reduction with AV-aidedinteractive guidance was evaluated. Each study consisted with twosessions with and without guidance to compare the intrafractional headmotion. Each session lasted for 5 minutes in the TrueBeam treatment roomfor the first study with one marker and in the CT simulation room forthe second study with two markers. The AV-aided interactive guidancetablet (i.e., unit #1) was placed above the subject's head (using aflexible tablet arm) for audiovisual guidance and the tracking marker(green colored) was placed on the nose of the subject as shown in FIG.1(A) (as can be observed on the display of the operator device 41 (e.g.,remote control table)) for the first study (five volunteers). For thesecond study with two markers, the tracking markers were placed on thenose of the subject and the area between the eyebrows (five volunteers:two of five volunteers participated in the first study (vol1 and vol2)).The other tablet (i.e., unit #2) was utilized for real-time remotecontrolling and monitoring (both can be performed within and outside thestudy room) during the session. Just for comparison purpose, eachparticipant performed one more session without AV-aided interactiveguidance. In the sessions without guidance, the system collected motiondata, and AV-aided interactive guidance was not given to the subject.The mean displacement was calculated by averaging the absolute values ofthe displacements (with horizontal and vertical data separate), and thebaseline shift was calculated by employing a linear fit on thedisplacements to determine the mm per minute baseline shift.

Results A. Basic Characteristics

The mean variation in positional accuracy was 0.3 mm independent on thenumber of markers, and the mean positional resolution was 0.2 mm. Themean variation in temporal accuracy was less than 0.6 ms, and the meantemporal resolution was 24 Hz (42 ms per data point—shown in FIG. 2).

B. Feasibility Test with Human Subjects

In the first study with one marker, intrafractional voluntary headmotion, in average, was kept within 0.5±0.4 mm and 0.3±0.1 mm forvertical- and horizontal-direction with guidance, respectively (see FIG.3), showing very promising performance while those without guidance were4.2±2.5 mm (vertically) and 1.3±1.2 mm (horizontally). Compared to thecase of no-guidance, the mean displacement was decreased vertically byan average of 88% and horizontally by an average of 77%. Noticeablepositional drift was also observed in the sessions without AV-aidedinteractive guidance. The average drift was decreased with AV guidancefrom 1.1±0.7 mm/min to 0.1±0.1 mm/min (91% reduction) vertically andfrom 0.3±0.2 mm/min to 0.1±0.1 mm/min (66% reduction) horizontally.

In the second study with two markers, average intrafractional voluntaryhead motion was 0.2±0.01 mm and 0.2±0.1 mm for vertical- andhorizontal-direction with guidance, respectively (see FIG. 4): 2.1±1.6mm (vertically) and 1.2±0.6 mm (horizontally) without guidance. The meandisplacement was decreased vertically by an average of 90% andhorizontally by an average of 83% using the AV-aided interactiveguidance. Positional drift was also observed without AV-aidedinteractive guidance. The average drift decreased from 0.4±0.3 mm/min to0.01±0.01 mm/min (95% reduction) vertically and from 0.3±0.3 mm/min to0.01±0.01 mm/min (86% reduction) horizontally with AV-aided interactiveguidance.

In the average displacement with two studies, it was reduced from 3.2 mmto 0.4 mm (vertical) and from 1.3 mm to 0.3 mm (horizontal) withaudiovisual guidance, respectively. In addition, the vertical andhorizontal baseline shift was reduced from 0.8 mm/min to 0.06 mm/min(vertical) and from 0.3 mm/min to 0.06 mm/min (horizontal) withaudiovisual guidance.

Discussion

In this study, a remote-controlled and self-contained audiovisual-aidedinteractive system of iPad minis with Retina display was developed andevaluated for intrafractional motion management. The system was testedusing the programmed QUASAR motion phantom in its resolution andaccuracy in both positional and temporal aspects, and showedsatisfactory performance (e.g., 0.2 mm positional resolution and 0.6 mstemporal resolution). When applied for human subjects, the system wasable to keep intrafractional head motion within a range acceptable forhigh precision (in average, 0.5 mm and 0.3 mm for vertical- andhorizontal-direction in the first study and 0.2 mm and 0.2 mm forvertical- and horizontal-direction in the second study, respectively).

This system and related method provides benefits as a self-containedsystem of tablet computers. It can be easily accessible by patients, andthey could potentially practice AV-aided interactive guidance usingtheir own personal device(s) at the waiting room or even at home. Notethat the AV-aided interactive guidance tablet can be used with completefunctionality without the remote control tablet. In addition, any iOSdevice, including iPhone and iPod, can substitute both the AV-aidedinteractive guidance and remote control components. The system is veryeasy to use (with most patients being familiar with iOS devices) andrequires relatively simple setup thus, can be implemented withoutdifficulty in most clinics even including places where resources arelimited. As mentioned, if the system is installed in waiting areas forpatients to practice before they begin radiation therapy treatments orCT simulation, it would improve not only delivery accuracy but also workflow efficiency.

The system utilizes tablet's built-in front-facing camera to detectmotion and consequently is constrained by the inherent resolution andlimitations of the camera. The system showed an error range of onepixel, and the corresponding error in millimeters depended on thedistance from the camera to the marker. For example, themillimeter-to-pixel ratio was 0.1 mm/pixel at 14 cm and 0.2 mm/pixel at25 cm. At greater distances, the positional resolution of the systemwould decrease. However, in practice, it is not likely to have such longdistance. As long as the camera is within 50 cm distance, under 1 mmresolution can be easily obtained. In addition, 10 mm head motion with 3degree rotation can be detected with 0.17% error by the system (20 cmaway from the marker).

In this study, the system tracked a single marker or two markers on thesubject's face and detected two translational degrees of freedom. In a3-dimensional space, three translational planes and three rotationalaxes exist thus, the 2-dimensional motion detection of the system didnot reflect true 3-dimensional motion. However, the tablet was close indistance to the subject's head, and the subjects were limited in theirmovements by the physiology of the human head and neck in lay-downposition. Therefore, we believe, 2-dimensional motion detection would besufficient for intrafractional head motion reduction in the current usecase. To extend functionality for other use cases, if it is absolutelynecessary, the system could utilize mobile 3D cameras for 3-dimensionalmotion tracing with the cost of adding little more complexity.

An aspect of an embodiment of the present invention system may include,but not limited thereto, two tablets, one for both motion tracing andaudiovisual guidance, and the other for remote control. With a routeroutside the treatment room wired to an access point inside the room, aninfrastructure Wi-Fi can be created and both tablets can communicatewith each other between the treatment and control rooms. The AV-aidedinteractive tablet streams frames captured from the front-facing camerato the remote control tablet and can potentially transmit other usefulinformation that can be easily monitored by the remote control tablet.Another benefit of an embodiment of the system, among others, is thatonly a single small mobile device is required in the treatment room forAV-aided interactive guidance, and the remote control device cancommunicate with the AV-aided interactive tablet anywhere outside of thetreatment room. Although the system is extremely simple andcost-effective compared to most commercially available motion managementsystems such as ExacTrac infrared camera system (BrainLab, Feldkirchen,Germany), AlignRT (Vision RT, Columbia, USA), RPM system, and ABC(Elekta, Stockholm, Sweden), it demonstrated a kind of unique andsufficient functionality of AV-aided interactive guidance.

For smooth clinical implementation, a similar feasibility study with anactual patient group is under consideration.

Conclusion

This study developed and demonstrated a self-contained AV-aidedinteractive system (and related method and computer readable medium)using easily obtainable and cost-effective tablet computers, with theiPad mini with Retina display. This approach can streamline clinicalflow with the proposed remote-controlled and self-contained system andby, among other things, allowing patients to practice self-motionmanagement before radiation treatment delivery.

Example and Experimental Results Set No. 2 Methods and Materials A.Self-Contained AV-Aided Interactive System

Refer to section above also referenced as “A. Self-contained AV-aidedinteractive system”.

B. Evaluation of Basic Characteristics

The positional accuracy and resolution of the system were investigatedthrough a phantom study using a programmable QUASAR motion phantom(Modus Medical Devices Inc., London, Canada) which is suitable for QAand assessment of motion with sub-millimeter accuracy shown in FIG. 2.(See J. Publicover, A. Vandermeer, B. Norrlinger, H. Alasti,“SU-GG-T-305: Feasibility of Using a Programmable Respiratory MotionPhantom for QA and Assessment of Dosimetric Implications of BreathingMotion During Radiation Therapy,” Medical Physics 35, 2795-2795 (2008)and L. Dunn, T. Kron, P. Johnston, L. McDermott, M. Taylor, J. Callahan,R. Franich, “A programmable motion phantom for quality assurance ofmotion management in radiotherapy,” Australasian Physical & EngineeringSciences in Medicine 35, 93-100 (2012); both disclosures of which areincorporated by reference herein.) The marker was moved with threedifferent positions (10 mm, 20 mm and 30 mm) using the programmed QUASARmotion phantom while the motion was detected and recorded by thetracking device. Tests were made in 15 cm, 30 cm and 50 cm of the markerplane-to-camera distance with parallel (right-left) or perpendicular(superior-inferior) motion.

The temporal accuracy and resolution of the system were studied with theQUASAR motion phantom which was set to oscillate with a peak-to-peakamplitude of 10 mm in a five second period. The temporal accuracy wasdetermined by averaging all peak-to-peak periods measured by the system.

The error resulting from rotational head movements detected by atwo-dimensional camera was simulated in most use cases of the system. Ageometric representation of the patient's head rotation with respect tothe camera, assuming that the back of the head is anchored by the headrest, is shown in the screenshot of FIG. 6, where h is the length of thehead from the forehead to the back of the head, δ is the symbol oflinear displacement, c is the distance from the camera (e.g., imageacquisition device) to the marker at δ=0, Δ is the actual lineardisplacement of the marker caused by the head rotation of θ, Φ is theangle of the camera seeing the displaced marker, d is the distance fromthe camera to the marker at δ=Δ, and Ω is the calculated displacement bythe system. It is noted that c, the distance from the camera to themarker at δ=0 is assumed to be 20 cm, and h, the length of the head isassumed to be 20 cm.

C. Feasibility Test with Human Subjects Simulating a ClaustrophobicBrain or H&N Case

A feasibility study of intrafractional head motion management for aclaustrophobic patient with H&N cancer was performed to investigate theeffectiveness of the system. To be conservative, the simulations werecarried out under the assumption that patients were severelyclaustrophobic, meaning that no immobilization device other than aheadrest was provided.

Ten healthy volunteers (age: 30.2±11.2, age range: 20˜52) participatedin the study and their voluntary head motion reductions with AV-aidedinteractive guidance were evaluated. Each study consisted of twosessions, one with and the other without guidance to compare theintrafractional head motion. For comparison purposes, thenon-interactive session was performed before the AV-aided interactivesession. In the sessions without guidance, the system collected motiondata while AV-aided interactive guidance was not given to the subject.Each session lasted for five minutes in the TrueBeam treatment room. TheAV-aided interactive tablet (unit #1) was placed above the subject'shead (using a flexible tablet holder) for AV-aided interactive guidance,and the tracking marker (green colored) was placed on the nose of thesubject as shown in FIG. 1. The other tablet (unit #2) was utilized forreal-time remote controlling and monitoring (both within and outside thestudy room) during the session.

The mean displacement was calculated by averaging the absolute values ofthe displacements (with right-left and superior-inferior data), and thepositional drift was calculated by employing a linear fit on thedisplacements to determine the mm per minute drift. Quantitativestatistical comparison of mean right-left and superior-inferiordisplacements, 95% confidence interval, and positional drift between thetwo sessions was performed using the paired Student's t-test andevaluated in a spreadsheet program (Excel 2010, Microsoft, Redmond,USA).

Results A. Basic Characteristics

The mean variation in positional accuracy was 0.3 mm, 0.8 mm and 0.8 mm,and the mean positional resolution was 0.2 mm, 0.3 mm and 0.5 mm with 15cm, 30 cm and 50 cm of the marker plane-to-camera distance,respectively. The mean variation in temporal accuracy was less than 0.6ms, and the mean temporal resolution was 24 Hz (42 ms per datapoint—shown in the screenshot of FIG. 2).

Three angular displacements of 0.28°, 1.43° and 2.86° rotation, in thesimulation as provided in the screenshot FIG. 6, caused 1 mm, 5 mm and10 mm translational motion, respectively. On the image plane, thedistances detected by the camera were 0.99 mm, 4.99 mm and 9.98 mm,respectively, resulting in not larger than 0.02 mm error within therange of angular displacement tested.

B. Feasibility Test with Human Subjects Simulating a ClaustrophobicBrain or H&N Case

In the study, intrafractional voluntary head motion, on average, waskept within 0.4±0.3 mm for the superior-inferior direction with guidance(FIG. 7(B)), showing promising performance while those without guidance(FIG. 7(A)) were 3.2±2.3 mm (p-value=0.002). In addition,intrafractional voluntary head motion in the right-left direction wasreduced from 1.3±0.9 mm without guidance (FIG. 7(A)) to 0.2±0.1 mm withguidance (FIG. 7(B)) (p-value=0.01). Compared to the case ofno-guidance, the mean displacement was decreased by an average of 89% inthe superior-inferior direction and by an average of 82% in theright-left direction.

Noticeable positional drift was also observed in the sessions withoutAV-aided interactive guidance, while the head position of the volunteersremained almost unchanged with guidance. The average drift was decreasedwith AV-aided interactive guidance from 0.8±0.6 mm/min to 0.1±0.1 mm/min(87% reduction, p-value=0.004) in the superior-inferior direction andfrom 0.3±0.2 mm/min to 0.1±0.1 mm/min (66% reduction, p-value=0.01) inthe right-left direction.

Referring to Table 1, the table demonstrates means displacement±standarddeviation (STD), baseline drift of the right-left and superior-inferiormotion, and paired Student t-test p-values with/without AV-aidedinteractive guidance.

TABLE 1 Mean Baseline Motion displacement ± 95% p- drift p- directionSTD (mm) Cl value (mm/min) value right-left No 1.3 ± 0.9 0~3.1 0.01 0.3± 0.2 0.01  guidance AV- 0.2 ± 0.1 0~0.4 0.1 ± 0.1 guidance (−82%)(−66%) superior- No 3.2 ± 2.3 0~7.8 <0.001 0.8 ± 0.6 0.004 inferiorguidance AV- 0.4 ± 0.3 0~1.0 0.1 ± 0.1 guidance (−89%) (−87%)

Discussion

In this study, a remote-controlled and self-contained audiovisual-aidedinteractive system of iPad minis with Retina display was developed forclaustrophobic patients with H&N cancer, and its resolution andaccuracy, as well as its efficacy when applied to human subjects, wereevaluated.

This system provides benefits as a self-contained system of tabletcomputers. In the study, intrafractional voluntary head motion wasreduced from 3.2 mm to 0.4 mm for the superior-inferior direction withguidance, suggesting the reduction of the CTV-PTV margins if the motionis properly managed. Another benefit is that it can be easily accessibleby patients, and they could potentially practice AV-aided interactiveguidance using their own personal device(s) at the waiting room or evenat home. Note that the AV-aided interactive tablet can be used withcomplete functionality without the remote control tablet. In addition,any iOS device, including iPhone and iPod, can substitute both theAV-aided interactive and remote control components. Due to thewidespread commercial availability and use of smart devices, such as iOSdevices, the volunteers were already familiar with the devices and hadno trouble using them. The system is simple to use and set up, and thus,it can be implemented without difficulty in most clinics, even includingplaces where resources are limited. As mentioned earlier, if the systemis installed in waiting areas for patients to practice before they beginradiation therapy treatments or CT simulation, it could improve not onlydelivery accuracy but also workflow efficiency.

The system utilizes the tablet's built-in front-facing camera to detectmotion and consequently is constrained by the inherent resolution andlimitations of the camera. The system showed an error range of onepixel, and the corresponding error in millimeters depended on thedistance from the camera to the marker. For example, themillimeter-to-pixel ratio was 0.2 mm/pixel at 15 cm and 0.3 mm/pixel at30 cm. At greater distances, the positional resolution of the systemwould decrease. In practice, however, it is not likely to have such longdistance. As long as the camera is within 50 cm, under 1 mm resolutioncan be obtained.

A limit of the system may be that the 2D motion tracking method of thecurrent system does not include motion in the third translationaldimension (anterior-posterior direction) and rotational errors in thecurrent system. However, the headrest or additional head supports securethe head position in the anterior-posterior direction. In addition, theerror resulting from rotational head movements detected by atwo-dimensional camera is not significant, if the rotational motion isnot huge. For example, as can be observed from FIG. 6, head displacementof around 10 mm caused by a 3 degree rotation would be detected within arelative error of about 0.2% by the system (at 20 cm away from themarker).

In this study, the system tracked a single marker on the subject's openface and detected two translational degrees of freedom. Specifically,the marker was placed on the nose assuming that the nose provides aprominent and relatively fixed area of the face for visual tracking. Ina three-dimensional space, three translational planes and threerotational axes exist thus, the two-dimensional motion detection of thesystem did not reflect true three-dimensional motion. However, thetablet was close in distance to the subject's head, and the subjectswere limited in their movements by the physiology of the human head andneck in supine position. Therefore, the present inventors believe,two-dimensional motion detection would be sufficient for intrafractionalhead motion reduction in the current use case. Although a test is notincluded in this study, the system can readily track multiple markers ondifferent areas of the face and display the mean displacement of them toobtain better accuracy, if needed. Furthermore, in principle,multi-body-part tracking can be realized using multiple units andmarkers placed on various body parts. In most head and neck cases, forinstance, not only the head but also other relevant body parts, such asshoulders and neck, are important. Therefore, their positions can beidentified and corrected during initial image guidance, and a mask onthe neck and shoulder can help the patient remain in place. However, ifa claustrophobic patient cannot tolerate a mask on the neck andshoulder, additional monitoring may be necessary, and two more iPads canbe arranged for real-time monitoring, one for the neck and the other forthe shoulders.

In the simulation of the study, the iPad was positionedanterior-inferiorly to the patient's face during treatment to monitorthe whole brain motion and to avoid direct irradiation to the iPad. Incases, however, some beam angles with couch kicks in IMRT or VMATtreatments interfere with the current iPad position, and so the iPad canbe placed more inferiorly with the aid of visual accessories, such asreflecting glasses.

This embodiment of the system may consist of, for example, two tablets,one for both motion tracing and audiovisual guidance, and the other forremote control. With a router outside the treatment room wired to anaccess point inside the room, an infrastructure Wi-Fi can be created andboth tablets can communicate with each other between the treatment andcontrol rooms. Although it should be appreciated that the router (s) maybe located inside, or outside, or a combination thereof. The AV-aidedinteractive tablet streams frames captured from the front-facing camerato the remote control tablet and can potentially transmit other usefulinformation that can be easily monitored by the remote control tablet.One of this system's benefits is that only a single small mobile deviceis required in the treatment room for AV-aided interactive guidance, andthe remote control device can communicate with the AV-aided interactivetablet anywhere outside of the treatment room.

The iPad close to the beam in the treatment room would be damaged byradiation. To our best knowledge, unfortunately, no systematic study ofradiation damage on the iPad has been reported. However, consideringthat planned replacement of iPad can be easily executed due to both theabundant availability and cost-effectiveness of the device, we believeradiation damage would not be a critical issue.

To bring the proposed system into the clinic, a couple of potentialissues need to be considered. First, the proposed 2D monitoring systemneeds to be verified with an independent system, such as 2D or 3Dradiographic imaging. Although the calculations illustrated in FIG. 6show that head displacement of around 10 mm with a 3 degree headrotation would be detected within a relative error of about 0.2%,verification with an independent imaging system can provide practicalguidelines on the use of the proposed system. Second, theaudiovisual-aided guidance method used in this study may not be optimalfor actual patients, who may have visual or auditory impairments.Therefore, an audiovisual-aided guidance that depends on the visual andauditory capabilities of the specific patient needs to be determinedprior to the procedure.

Compared to the most commercially available motion management systems,such as ExacTrac infrared camera system, AlignRT, Real-time PositioningManagement (RPM) system (Varian Medical Systems, Palo Alto, USA), andActive Breath Hold (ABC) system (Elekta, Stockholm, Sweden), withlimited accessibility by patients, the proposed system is cost-effectiveso its unique and sufficient functionality of AV-aided interactiveguidance in the treatment room as well as in the waiting room can beutilized without substantial financial burden.

Conclusion

This study developed and demonstrated a self-contained AV-aidedinteractive system for claustrophobic patients with brain or H&N cancerusing easily obtainable and cost-effective tablet computers only (iPadmini with Retina display). This approach can potentially streamlineclinical flow for claustrophobic patients without a head mask and byallowing patients to practice self-motion management before radiationtreatment delivery. To bring the proposed 2D tracking system into theclinic, it needs to be verified with an independent 2D or 3D imagingsystem.

ADDITIONAL EXAMPLES Example 1

An aspect of an embodiment of the present invention provides, but notlimited thereto, a system for reducing intrafractional motion of asubject The system may comprise a subject user device, whereby the userdevice may comprise an image acquisition device configured to receivelocation marker information of the subject to provide location markingdata of the subject. The system may comprise: a digital processorconfigured to: receive the location marking data and determine movementof the subject relative to the location marker information; andcommunicate feedback of the movement to the subject to help the subjectreduce intrafractional motion.

Example 2

The system of example 1, wherein the communication feedback to thesubject is in real time.

Example 3

The system of example 1 (as well as subject matter of example 2),wherein the communication feedback of the movement to the subjectincludes: visual display, audio signal, or both visual and audio.

Example 4

The system of example 3 (as well as subject matter of one or more of anycombination of examples 2-3), wherein the visual display is a displaypanel in communication with the subject user device and which isviewable by the subject.

Example 5

The system of example 4 (as well as subject matter of one or more of anycombination of examples 2-3), wherein the digital processor determines areference point and a movement point, wherein: the reference pointrepresents a starting position of the subject; and the movement pointrepresents an indication of intrafractional motion of the subject.

Example 6

The system of example 4 (as well as subject matter of one or more of anycombination of examples 2-3 or 5), wherein display panel includes adisplay reference point and a display movement point, wherein: thereference point represents to a subject a starting position of thesubject; and the display movement point represents to a subject anindication of intrafractional motion of the subject.

Example 7

The system of example 6 (as well as subject matter of one or more of anycombination of examples 2-5), wherein: the display reference point is afirst color having a preselected pattern, and the display movement pointis a second color having a preselected pattern, wherein theintrafractional motion causes the display movement point to moverelative to the reference point, and that which is discernable to thesubject.

Example 8

The system of example 3 (as well as subject matter of one or more of anycombination of examples 2 or 4-7-), wherein the audio signal is providedby a speaker in communication with the subject user device and which isaudible by the subject.

Example 9

The system of example 1 (as well as subject matter of one or more of anycombination of examples 2-8), further comprising: an operator device,the operator device comprising: an operator digital processor configuredto communicate with the subject user device.

Example 10

The system of example 9 (as well as subject matter of one or more of anycombination of examples 2-9), wherein the operator digital processor isconfigured to control and/or monitor the user device.

Example 11

The system of example 9 (as well as subject matter of one or more of anycombination of examples 2-8 or 10), wherein the operator devicecomprises at least one of the following: video display, alpha-numericinput device, or UI navigation device for controlling or monitoring theuser device.

Example 12

The system of example 1 (as well as subject matter of one or more of anycombination of examples 2-11), wherein the digital processor isconfigured to control the user device.

Example 13

The system of example 1 (as well as subject matter of one or more of anycombination of examples 2-12), wherein the location marker informationof the subject is provided by the following: a marking substratedisposed on the subject; a location identified on the subject; or acombination of a marking substrate disposed on the subject and alocation identified on the subject.

Example 14

The system of example 1 (as well as subject matter of one or more of anycombination of examples 2-13), wherein the determination of movement ofthe subject is provided by configuring a geometric representation ofrotation of the head of the subject.

Example 15

The system of example 14 (as well as subject matter of one or more ofany combination of examples 2-13), wherein the geometric representationof rotation of the head of the subject is provided according to thefollowing characteristics:

h, wherein h is the length of the head from the forehead to the back ofthe head,

δ, wherein δ is the symbol of linear displacement,

c, wherein c is the distance from the image acquisition device to amarker at δ=0,

Δ, wherein Δ is the actual linear displacement of the marker caused bythe head rotation of θ,

Φ, wherein Φ is the angle of the image acquisition device seeing thedisplaced marker,

d, wherein d is the distance from the image acquisition device to themarker at δ=Δ, and

Ω, wherein Ω is the calculated displacement by the system.

Example 16

An aspect of an embodiment of the present invention provides, but notlimited thereto, a computer implemented method for reducingintrafractional motion of a subject. The method may comprise: receivinglocation marker information of the subject and generating locationmarking data of the subject; digitally processing the location markingdata and determining movement of the subject relative to the locationmarker information; and communicating feedback of the movement to thesubject to help the subject reduce intrafractional motion.

Example 17

The method of example 16, wherein the communicating the feedback to thesubject is performed in real time.

Example 18

The method of example 16 (as well as subject matter of example 17),wherein the communicating the feedback of the movement to the subjectincludes:

visually displaying the feedback to the subject, audibly signaling thefeedback to the subject, or both visually displaying and audiblysignaling to the subject.

Example 19

The method of example 16 (as well as subject matter of one or more ofany combination of examples 17-18), wherein the digital processingdetermines a reference point and a movement point, wherein: thereference point represents a starting position of the subject; and themovement point represents an indication of intrafractional motion of thesubject.

Example 20

The method of example 19 (as well as subject matter of one or more ofany combination of examples 17-19), wherein: the reference point isassociated with a first alarm having a preselected audible tone orpitch, and the movement point is associated with a second alarm having apreselected audible tone or pitch, wherein the intrafractional motioncauses the second alarm to activate, which is audibly discernable to thesubject.

Example 21

The method of example 16 (as well as subject matter of one or more ofany combination of examples 17-20), further comprising: operating acontroller, wherein operating the controller includes controlling thedigital processing and/or the communicating of the feedback.

Example 22

The method of example 21 (as well as subject matter of one or more ofany combination of examples 17-20), wherein the operating the controlleris performed with at least one of the following: video display,alpha-numeric input device, or UI navigation device.

Example 23

The method of example 16 (as well as subject matter of one or more ofany combination of examples 17-22), wherein the location markerinformation of the subject is provided by the following: providing amarking substrate disposed on the subject; identifying a location on thesubject; or a combination of providing a marking a substrate disposed onthe subject and identifying a location on the subject.

Example 24

The method of example 16 (as well as subject matter of one or more ofany combination of examples 17-23), wherein the determination ofmovement of the subject is provided by configuring a geometricrepresentation of rotation of the head of the subject.

Example 25

The method of example 24 (as well as subject matter of one or more ofany combination of examples 17-23), wherein the geometric representationof rotation of the head of the subject is provided according to thefollowing characteristics:

h, wherein h is the length of the head from the forehead to the back ofthe head,

δ, wherein δ is the symbol of linear displacement,

c, wherein c is the distance from the image acquisition device to amarker at δ=0,

Δ, wherein Δ is the actual linear displacement of the marker caused bythe head rotation of θ,

Φ, wherein Φ is the angle of the image acquisition device seeing thedisplaced marker,

d, wherein d is the distance from the image acquisition device to themarker at δ=Δ, and

Ω, wherein Ω is the calculated displacement by the system.

Example 26

An aspect of an embodiment of the present invention provides, but notlimited thereto, a non-transitory machine readable medium includinginstructions for reducing intrafractional motion of a subject, whichwhen executed by a machine, cause the machine to: receive locationmarker information of the subject and generate location marking data ofthe subject; determine movement of the subject relative to the locationmarker information; and transmit to an output module to communicatefeedback of the movement to the subject to help the subject reduceintrafractional motion.

Example 27

The non-transitory medium of claim 26, wherein the output modulecomprises one or more of the following: memory storage, memory, network,display, or speaker.

Example 28

The non-transitory medium of claim 26, including instructions forreducing intrafractional motion of a subject, which when executed by amachine is capable of performing any one or more of the steps of one ormore of Examples 16-25.

Example 29

A method of making or using the system (or portions of the system) asprovided in any one or more of Examples 1-14.

REFERENCES

The following patents, applications and publications as listed below andthroughout this document are hereby incorporated by reference in theirentirety herein (and which are not admitted to be prior art with respectto the present invention by inclusion in this section):

-   ¹ T. Yamamoto, U. Langner, B. W. Loo Jr, J. Shen, P. J. Keall,    “Retrospective Analysis of Artifacts in Four-Dimensional CT Images    of 50 Abdominal and Thoracic Radiotherapy Patients,” International    Journal of Radiation Oncology*Biology*Physics 72, 1250-1258 (2008).-   ² S. Kim, Y.-K. Park, J. Lee, K. Choi, S.-J. Ye, “Double-ends    quasi-breath-hold (DE-QBH) technique for respiratory motion    management,” Med Phys 40, 1 (2013).-   ³ S. Kim, H. C. Akpati, J. G. Li, C. R. Liu, R. J. Amdur, J. R.    Palta, “An immobilization system for claustrophobic patients in    head-and-neck intensity-modulated radiation therapy,” International    Journal of Radiation Oncology*Biology*Physics 59, 1531-1539 (2004).-   ⁴ G. C. Bentel, L. B. Marks, K. Hendren, D. M. Brizel, “Comparison    of two head and neck immobilization systems,” International Journal    of Radiation Oncology*Biology*Physics 38, 867-873 (1997).-   ⁵ P. Keall, G. Mageras, J. Balter, R. Emery, K. Forster, S.    Jiang, J. Kapatoes, D. Low, M. Murphy, B. Murray, C. Ramsey, M. Van    Herk, S. Vedam, J. Wong, E. Yorke, “The management of respiratory    motion in radiation oncology report of AAPM Task Group 76,” Med Phys    33, 3874-3900 (2006).-   ⁶ R. B. Venkat, A. Sawant, Y. Suh, R. George, P. J. Keall,    “Development and preliminary evaluation of a prototype audiovisual    biofeedback device incorporating a patient-specific guiding    waveform,” Physics in medicine and biology 53, N197 (2008).-   ⁷ S. Kim, R. D. Helmig, “Interactive patient immobilization system,”    (Google Patents, 2010).-   ⁸ S. K. Kim, H. Chung, H. Jin, J. Palta, T.-S. Suh, R. Helmig,    “Laser-Guided Interactive Patient Immobilization System for the    Brain or Head and Neck Treatment” Medical physics; ICMP (14th),    838-839 (2005).-   ⁹ R. George, T. D. Chung, S. S. Vedam, V. Ramakrishnan, R. Mohan, E.    Weiss, P. J. Keall, “Audio-visual biofeedback for respiratory-gated    radiotherapy: Impact of audio instruction and audio-visual    biofeedback on respiratory-gated radiotherapy,” Int J Radiat Oncol    Biol Phys 65, 924-933 (2006).-   ¹⁰ T. Kim, S. Pollock, D. Lee, R. O'Brien, P. Keall, “Audiovisual    biofeedback improves diaphragm motion reproducibility in MRI,”    Medical Physics 39, 6921 (2012).-   ¹¹ S. Lim, S. H. Park, S. D. Ahn, Y. Suh, S. S. Shin, S.-w.    Lee, J. H. Kim, E. K. Choi, B. Y. Yi, S. I. Kwon, S. Kim, T. S.    Jeung, “Guiding curve based on the normal breathing as monitored by    thermocouple for regular breathing,” Medical Physics 34, 4514-4518    (2007).-   ¹² J. F. T. Arnold, P. Mörchel, E. Glaser, E. D. Pracht, P. M.    Jakob, “Lung MRI using an MR-compatible active breathing control    (MR-ABC),” Magnetic Resonance in Medicine 58, 1092-1098 (2007).-   ¹³ T. Kim, R. Pooley, D. Lee, P. Keall, R. Lee, S. Kim,    “Quasi-breath-hold (QBH) Biofeedback in Gated 3D Thoracic MRI:    Feasibility Study,” Progress in Medical Physics 25, 72-78 (2014).-   ¹⁴ Y. K. Park, S. Kim, H. Kim, I. I. H. Kim, K. Lee, S. J. Ye,    “Quasi-breath-hold technique using personalized audio-visual    biofeedback for respiratory motion management in radiotherapy,”    Medical Physics 38, 3114 (2011).-   ¹⁵ S. J. McKenna, Y. Raja, S. Gong, “Tracking colour objects using    adaptive mixture models,” Image and vision computing 17, 225-231    (1999).

The devices, systems, non-transitory computer readable medium,components, modules, and methods of various embodiments of the inventiondisclosed herein may utilize aspects disclosed in the followingreferences, applications, publications and patents and which are herebyincorporated by reference herein in their entirety (and which are notadmitted to be prior art with respect to the present invention byinclusion in this section):

-   A. Kim, S., et al., “An Immobilization System for Claustrophobic    Patients in Head-and-Neck Intensity-Modulated Radiation Therapy”,    Int. J. Radiation Oncology Biol. Phys., Vol. 59, No. 5, pp.    1531-1539, 2004.-   B. Li, G., et al., “Migration from full-head mask to “open-face”    mask for immobilization of patients with head and neck cancer”,    Journal of Applied Clinical Medical Physics, Vol. 14, No. 5, 2013,    pp 243-254.-   C. U.S. Patent Application Publication No. US 2007/0093723 A1,    Keall, et al., “Method and Apparatus for Respiratory Audio-Visual    Biofeedback for Imaging and Radiotherapy”, Apr. 26, 2007.-   D. International Patent Application Serial No. WO 2014/116868 A1,    Yu, et al., “Systems, Devices, and Methods for Tracking and    Compensating for Patient Motion During a Medical Imaging Scan”, Jul.    31, 2014.-   E. U.S. Patent Application Publication No. US 2013/0289796 A1,    Bergfjord, et al., “Vision System for Radiotherapy Machine    Operator”, Oct. 31, 2013.-   F. International Patent Application Publication No. WO 2012/033739    A2, Karahalios, et al., “Surgical and Medical Instrument Tracking    Using a Depth-Sensing Device”, Mar. 15, 2012.-   G. U.S. Pat. No. 8,754,805 B2, Wang, et al., “Method and Apparatus    for Image-Based Positioning”, Jun. 17, 2014.

It should be appreciated that any of the components or modules referredto with regards to any of the present invention embodiments discussedherein, may be integrally or separately formed with one another.Further, redundant functions or structures of the components or modulesmay be implemented. Moreover, the various components may be communicatedlocally and/or remotely with any user/clinician/patient ormachine/system/computer/processor. Moreover, the various components maybe in communication via wireless and/or hardwire or other desirable andavailable communication means, systems and hardware. Moreover, variouscomponents and modules may be substituted with other modules orcomponents that provide similar functions.

In summary, while the present invention has been described with respectto specific embodiments, many modifications, variations, alterations,substitutions, and equivalents will be apparent to those skilled in theart. The present invention is not to be limited in scope by the specificembodiment described herein. Indeed, various modifications of thepresent invention, in addition to those described herein, will beapparent to those of skill in the art from the foregoing description andaccompanying drawings. Accordingly, the invention is to be considered aslimited only by the spirit and scope of the following claims, includingall modifications and equivalents.

Still other embodiments will become readily apparent to those skilled inthis art from reading the above-recited detailed description anddrawings of certain exemplary embodiments. It should be understood thatnumerous variations, modifications, and additional embodiments arepossible, and accordingly, all such variations, modifications, andembodiments are to be regarded as being within the spirit and scope ofthis application. For example, regardless of the content of any portion(e.g., title, field, background, summary, abstract, drawing figure,etc.) of this application, unless clearly specified to the contrary,there is no requirement for the inclusion in any claim herein or of anyapplication claiming priority hereto of any particular described orillustrated activity or element, any particular sequence of suchactivities, or any particular interrelationship of such elements.Moreover, any activity can be repeated, any activity can be performed bymultiple entities, and/or any element can be duplicated. Further, anyactivity or element can be excluded, the sequence of activities canvary, and/or the interrelationship of elements can vary. Unless clearlyspecified to the contrary, there is no requirement for any particulardescribed or illustrated activity or element, any particular sequence orsuch activities, any particular size, speed, material, dimension orfrequency, or any particularly interrelationship of such elements.Accordingly, the descriptions and drawings are to be regarded asillustrative in nature, and not as restrictive. Moreover, when anynumber or range is described herein, unless clearly stated otherwise,that number or range is approximate. When any range is described herein,unless clearly stated otherwise, that range includes all values thereinand all sub ranges therein. Any information in any material (e.g., aUnited States/foreign patent, United States/foreign patent application,book, article, etc.) that has been incorporated by reference herein, isonly incorporated by reference to the extent that no conflict existsbetween such information and the other statements and drawings set forthherein. In the event of such conflict, including a conflict that wouldrender invalid any claim herein or seeking priority hereto, then anysuch conflicting information in such incorporated by reference materialis specifically not incorporated by reference herein.

We claim:
 1. A system for reducing intrafractional motion of a subject,the system comprising: a subject user device, said user devicecomprising: an image acquisition device configured to receive locationmarker information of the subject to provide location marking data ofthe subject; a digital processor configured to: receive said locationmarking data and determine movement of the subject relative to thelocation marker information; and communicate feedback of the movement tothe subject to help the subject reduce intrafractional motion.
 2. Thesystem of claim 1, wherein said communication feedback to the subject isin real time.
 3. The system of claim 1, wherein said communicationfeedback of the movement to the subject includes: visual display, audiosignal, or both visual and audio.
 4. The system of claim 3, wherein saidvisual display is a display panel in communication with said subjectuser device and which is viewable by the subject.
 5. The system of claim4, wherein said digital processor determines a reference point and amovement point, wherein: said reference point represents a startingposition of the subject; and said movement point represents anindication of intrafractional motion of the subject.
 6. The system ofclaim 4, wherein display panel includes a display reference point and adisplay movement point, wherein: said reference point represents to asubject a starting position of the subject; and said display movementpoint represents to a subject an indication of intrafractional motion ofthe subject.
 7. The system of claim 6, wherein: said display referencepoint is a first color having a preselected pattern, and said displaymovement point is a second color having a preselected pattern, whereinthe intrafractional motion causes the display movement point to moverelative to the reference point, and that which is discernable to thesubject.
 8. The system of claim 3, wherein said audio signal is providedby a speaker in communication with said subject user device and which isaudible by the subject.
 9. The system of claim 1, further comprising: anoperator device, said operator device comprising: an operator digitalprocessor configured to communicate with said subject user device. 10.The system of claim 9, wherein said operator digital processor isconfigured to control and/or monitor said user device.
 11. The system ofclaim 9, wherein said operator device comprises at least one of thefollowing: video display, alpha-numeric input device, or UI navigationdevice for controlling or monitoring said user device.
 12. The system ofclaim 1, wherein said digital processor is configured to control saiduser device.
 13. The system of claim 1, wherein said location markerinformation of the subject is provided by the following: a markingsubstrate disposed on the subject; a location identified on the subject;or a combination of a marking substrate disposed on the subject and alocation identified on the subject.
 14. The system of claim 1, whereinsaid determination of movement of the subject is provided by configuringa geometric representation of rotation of the head of the subject. 15.The system of claim 14, wherein said geometric representation ofrotation of the head of the subject is provided according to thefollowing characteristics: h, wherein h is the length of the head fromthe forehead to the back of the head, δ, wherein δ is the symbol oflinear displacement, c, wherein c is the distance from said imageacquisition device to a marker at δ=0, Δ, wherein Δ is the actual lineardisplacement of said marker caused by the head rotation of θ, Φ, whereinΦ is the angle of said image acquisition device seeing the displacedmarker, d, wherein d is the distance from said image acquisition deviceto the marker at δ=Δ, and Ω, wherein Ω is the calculated displacement bythe system.
 16. A computer implemented method for reducingintrafractional motion of a subject, the method comprising: receivinglocation marker information of the subject and generating locationmarking data of the subject; digitally processing said location markingdata and determining movement of the subject relative to the locationmarker information; and communicating feedback of the movement to thesubject to help the subject reduce intrafractional motion.
 17. Themethod of claim 16, wherein said communicating the feedback to thesubject is performed in real time.
 18. The method of claim 16, whereinsaid communicating the feedback of the movement to the subject includes:visually displaying said feedback to the subject, audibly signaling saidfeedback to the subject, or both visually displaying and audiblysignaling to the subject.
 19. The method of claim 16, wherein saiddigital processing determines a reference point and a movement point,wherein: said reference point represents a starting position of thesubject; and said movement point represents an indication ofintrafractional motion of the subject.
 20. The method of claim 19,wherein: said reference point is associated with a first alarm having apreselected audible tone or pitch, and said movement point is associatedwith a second alarm having a preselected audible tone or pitch, whereinthe intrafractional motion causes the second alarm to activate, which isaudibly discernable to the subject.
 21. The method of claim 16, furthercomprising: operating a controller, wherein operating the controllerincludes controlling said digital processing and/or said communicatingof the feedback.
 22. The method of claim 21, wherein said operating thecontroller is performed with at least one of the following: videodisplay, alpha-numeric input device, or UI navigation device.
 23. Themethod of claim 16, wherein said location marker information of thesubject is provided by the following: providing a marking substratedisposed on the subject; identifying a location on the subject; or acombination of providing a marking a substrate disposed on the subjectand identifying a location on the subject.
 24. The method of claim 16,wherein said determination of movement of the subject is provided byconfiguring a geometric representation of rotation of the head of thesubject.
 25. The method of claim 24, wherein said geometricrepresentation of rotation of the head of the subject is providedaccording to the following characteristics: h, wherein h is the lengthof the head from the forehead to the back of the head, δ, wherein δ isthe symbol of linear displacement, c, wherein c is the distance fromsaid image acquisition device to a marker at δ=0, Δ, wherein Δ is theactual linear displacement of said marker caused by the head rotation ofθ, Φ, wherein Φ is the angle of said image acquisition device seeing thedisplaced marker, d, wherein d is the distance from said imageacquisition device to the marker at δ=Δ, and Ω, wherein Ω is thecalculated displacement by the system.
 26. A non-transitory machinereadable medium including instructions for reducing intrafractionalmotion of a subject, which when executed by a machine, cause the machineto: receive location marker information of the subject and generatelocation marking data of the subject; determine movement of the subjectrelative to the location marker information; and transmit to an outputmodule to communicate feedback of the movement to the subject to helpthe subject reduce intrafractional motion.
 27. The non-transitory mediumof claim 26, wherein said output module comprises one or more of thefollowing: memory storage, memory, network, display, or speaker.